In the fabrication of semiconductor devices such as integrated circuits, memory cells, and the like, a series of manufacturing operations are performed to define features on semiconductor wafers (“wafers”). The wafers (or substrates) include integrated circuit devices in the form of multi-level structures defined on a silicon substrate. At a substrate level, transistor devices with diffusion regions are formed. In subsequent levels, interconnect metallization lines are patterned and electrically connected to the transistor devices to define a desired integrated circuit device. Also, patterned conductive layers are insulated from other conductive layers by dielectric materials.
During the series of manufacturing operations, the wafer surface is exposed to various types of contaminants. Essentially any material present in a manufacturing operation is a potential source of contamination. For example, sources of contamination may include process gases, chemicals, deposition materials, and liquids, among others. The various contaminants may deposit on the wafer surface and at the wafer edge in particulate form. Particulate contamination can cause devices within the vicinity of the contamination to be inoperable. It should be appreciated that the manufacturing operations for flat panel displays suffer from the same shortcomings of the integrated circuit manufacturing discussed above.
During processing of a substrate by a liquid meniscus, such contamination may be spread about the wafer by the meniscus itself. This can result in the spread of the contaminating particles to other portions of the substrate, possibly rendering other devices or features inoperable in the process.
In view of the foregoing, there is a need for apparatus and methods of processing wafers that are effective in preventing the spread of contaminants upon a wafer surface. It is in this context that embodiments of the invention arise.